1. Field of the Invention:
The present invention relates to a mounting system for assembling various components of an airbag module, and more particularly, to a system having offset mounting means for positively orienting an inflator, retaining ring, cushion and housing assembly for driver side airbag modules.
2. Description of the Related Art:
During the manufacture of an airbag module of a vehicle safety system a plurality of components must be assembled. Among the components of the airbag module are the cover, airbag cushion, airbag clamping means (an annular retaining ring, module housing and fasteners), inflator, ignitor and means to attach the assembled module to the body of the automobile.
In a conventional airbag mounting, the peripheral region around the outer circumference of the gas inlet opening into the airbag is clamped between a module housing provided around the gas discharge or exit opening and an annular retainer secured to the module housing. The annular retainer is bolted or riveted to the module housing, see U.S. Pat. No. 5,443,284, assigned to the assignee of the present invention.
Deployment produced forces tend to pull and separate the airbag cushion from its mounting. Such mountings may be insufficient to prevent separation of the bag from the housing, Also rivets, etc. may break entering the passenger compartment along with the gas, endangering the vehicle occupants.
Both riveting and bolting require another step in the manufacturing process, which serves to delay production by increasing the time needed to produce the airbag module assembly. Moreover, workmen often must spend and inordinate amount of time trying to line up the corresponding holes of the components for insertion of the bolts and or rivets. If a misorientation does occur, reworking of the module is necessary and sometimes not possible. Often module parts cannot be reworked and must be discarded, resulting in increased production times and costs.
Although there are many visual, operator dependent methods for orienting the cushion, retaining ring, housing and inflator, for example, by coloring an edge of the airbag, such methods are strictly visual and misorientation of the components by the operator can still occur during assembly.
Misorientations of the airbag cushions with discrete vents can also cause burns to the vehicle occupant during deployment. If the vents are positioned improperly during assembly, the deployed gases will be directed downwardly toward the vehicle occupant.
Thus, a system and method for positively orientating the components of the airbag module is needed, without relying strictly on visual alignments by the production associates.
An object of the present invention is to provide a mounting system for eliminating misorientations of the components of the airbag module during assembly.
Another object of the present invention is to provide an assembly system which correctly aligns the components of an airbag module in a simple and inexpensive manner.
Still another object of the present invention is to provide a mounting system which does not strictly rely on visual orientation of a production associate.
In accomplishing these and other objectives of the present invention, there is provided an airbag mounting system for orienting an inflator, a retaining ring, an airbag cushion and a housing module of an airbag module assembly. The assembly includes an annular retaining ring having a plurality of first fastener openings circumferentially spaced about the ring. At least two of the plurality of first fastener openings being spaced from each other along the ring circumference by a first angle. At least one of the plurality of first fastener openings is offset from at least one of the at least two first fastener openings by a second angle different from the first angle. A module housing includes a plurality of second fastener openings circumferentially spaced about a central inlet opening. At least two of the second fastener openings are spaced from each other along the circumference by a third angle. At least one of the second fastener openings is offset from at least one of the at least two second openings by a fourth angle which is different from the third angle. An airbag having a gas inlet opening corresponding with the central opening of the module housing includes a plurality of third fastener openings circumferentially spaced about the gas inlet opening. At least two of the third fastener openings are spaced from each other along the circumference by a fifth angle. At least one of the third fastener openings is spaced from at least one of the at least two third openings by a sixth angle different from the fifth angle. Upon assembly the at least one of the first fastener openings is aligned with the at least one of the second and third fastener openings. Fastening means extend through the plurality of first, second fastener openings and the at least one of the third fastener openings for securing the retaining ring, airbag and housing module together.